Coastdown Timing.

[IDRIVEAG8GT]

So.... I know this problem has been discussed several times before, and I know exactly what the problem is but I'm unsure of how to go about fixing it. It goes like this:

On a customers cammed 09 G8 GT is doing well until you let off the throttle, for awhile it follows the VSS commanded idle versus speed, but then all the sudden the timing just drops out of it, bouncing around between -3 and 16 degrees fairly rapidly which creates an unpleasant surge like you're on and off the brakes repeatedly.

However in manual mode, the problem is totally gone, no timing faltering, and no surging. I'm on my iPhone at the moment, so no log or tune, but do any of you have a quick suggestion on how to modify the timing coastdiwn tables?

Thanks,
-Robbie.

[IDRIVEAG8GT]

Nevermind I got it fixed. When the TCC stayed locked it brought the commanded idle above commanded so it decided to unlock the TCC and retard timing to try and bring the idle speed back down.

Good to go now

[01 MidMet WS6]

So what was your fix for the problem? I am getting going on one that is doing the exact same thing right now.